Effect of hydraulic retention time and pH on oxidation of ferrous iron in simulated ferruginous acid mine drainage treatment with inoculation of iron-oxidizing bacteria

The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (about 1700 mg/L) and copper (about 200 mg/L), and contained high concentrations of sulfate (about 4700 mg/L).The biooxidation of ferrous iron was studied in a laboratory-scale upflow packed bed bioreactor (PBR).The HRT was shortened stepwise from 40 h to 20 h, 13 h, and 8 h under the acidic environment at a pH value of 2.2.Then, the influent pH value was changed from 2.2 to 1.2 at a constant suitable HRT.Physiochemical and microbial community structure analyses were performed on water samples and stuffing collected from the bioreactor under different conditions.The results indicate that the efficiency of ferrous iron oxidation gradually decreased with the decrease of HRT, and when the HRT exceeded 13 h, ferrous iron in AMD was almost completely oxidized.In addition, the best efficiency of ferrous iron oxidation was achieved at the influent pH value of 1.8.Microbial community structure analyses show that Leptospirillum is the predominant genus attached in the bioreactor, and low influent pH values are suitable for the growth of Leptospirillum.

Regulation of MRI contrast and cellular retention time by cellular interfacial distribution of Gd agents:Implications for stem cell tracking

Human mesenchymal stem cells(hMSCs)were labeled with Dotarem or(Gd-DOTA)2-EM7(EM7Gd2)via electroporation(EP).Cellular transmission electron microscopy(TEM)reveals free distribution of Gd agents and formation of EM7Gd2 clusters in the cytosol.Cellular magnetic resonance imaging(MRI)reveals that the free Gd agents induce MRI signal enhancement effect due to its fast exocytosis and subsequent interaction with intercellular water molecules.The EM7Gd2 clusters exhibits a longer intracellular retention time and induce a persistent MRI signal reduction effect.The cellular MRI results are interpreted by taking into account both T1 and T2 relaxation rates and their correlation with cellular binding structures of Dotarem and EM7Gd2.

APPLICATION OF BORON MODIFIED SILICA SOL ON RETENTION AND DRAINAGE

In this paper it was studied that these dosage effects of CPAM, cationic starch?boron modified silica sol(BMS), Al2(SO4)3, pH value and electrolyte on the retention and drainage of different microparticulate systems including CPAM, cationic starch and boron silica sol. The research results indicated that CPAM had no good retention when used with boron silica sol. The best retention efficiency was the microparticulate system of CPAM + cationic starch with boron modified silica sol; Secondly was that of cationic starch with boron modified silica sol; The worst was that of CPAM with boron modified silica sol. The retention efficiency had no relation with the addition order between CPAM and cationic starch. It was also found that the microparticulate retention system of boron modified silica sol could be used in alum-rosin sizing and in acidity, neutral or alkaline papermaking conditions. This system also could be used with close circulate water so that it could reduce the water pollution and waste.

STDUY ON RETENTION AND DRAINAGE PROPERTIES OF THE HIGH SUBSTITUTED DEGREE CATIONIC STARCH

This paper deals with the retention and drainage properties of the high substituted degree cationic starch (HCS) prepared by half-dry process. The experiments show that HCS has remarkable effects on filler retention and drainage in papermaking industry. With the degree of substitution (DS) of HCS increasing, the effects on filler retention and drainage increase. When the DS of HCS is 0.509 and the dosage is 0.08%, the freeness decreases about 12oSR and the filler retention is 79.82%.

APPLICATION OF CATIONIC POLYMERIC MICROPARTICLES ON RETENTION AND DRAINAGE

The conditions of preparation and performance of a new structure of cationic organic polymeric micropaticles (CPMP) mainly composed of styrene and DADMAC were studied. And its application on retention and drainage on bleached hardwood pulp was investigated and compared with that of APAM and CPAM. The results show that the retention and drainage of CPMP on pulp is in positive proportion to the rise of the potential of the solution, and the first-pass retention ratio of bleached hardwood pulp goes up with the increase of the CPMP content. The functions of CPMP and CPAM are affected less by the shear force and the pH value of the system compared to that of APAM, and effect on retention of CPMP3 is appropriate to that of CPAM, but superior to that of APAM.

Combined urethral and suprapubic catheter drainage improves post operative management after open simple prostatectomy without bladder irrigation

AIM To compare outcomes after open simple prostatectomy without bladder irrigation, in subjects drained by combined 2-way urethral catheter and suprapubic catheter(SPC) vs those drained by 2-way urethral catheter only.METHODS A total of 84 participants undergoing Freyer's simple prostatectomy over an 18-mo period were randomized into 2 groups(n=42). Subjects in group 1 were managed with 2-way urethral catheter and in situ 2-way SPC while subjects in group 2 had a 2-way urethral catheter drainage only. In group 1 subjects, the SPC was spigotted and only used for drainage if there was clot retention. The primary outcomes were number of clot retention episodes, and number of clot retention episodes requiring bladder syringe evacuation. Other secondary outcomes evaluated were blood loss, requirement of extra analgesics, duration of surgery, hospital stay and presence or absence of post-op complications. RESULTS The mean age in the groups was 65.7(± 7.6) in group 1 vs 64.8(±6.8) in group 2.The groups were similar with respect to age, prostate specific antigen, prostate volume, blood loss, duration of surgery, blood transfusion and overall complication rate. However statistically significant differences were observed in clot retention episodes between group 1 and 2:0.8(±1.5)vs3.5(±4.4), P<0.000, clot retention episodes requiring evacuation with bladder syringe 0.4(± 0.9) vs 2.6(± 3.8), P = 0.001, requirement of extra analgesics 0.4(±0.5)vs4.0(±1.5), P<0.000 and duration of admission 8.6d(± 1.2) vs 7.3 CONCLUSION Subjects drained with a combination of urethral and SPCs have fewer clot retention episodes and reduced requirement of extra analgesics but slightly longer hospital stay.

APPLICATION OF CATIONIC STARCH BY DRY-PROCESS AS ANIONIC CHARGE NEUTRALIZING AGENTS TO IMPROVE FILLER RETENTION

This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride). The reacting time is for 5 hours at the temperature of 70℃. The cationic starch with high degree of substitution is used as anionic charge neutralizing agents to improve filler retention in wet-end section of papermaking machine.

Nanoparticle foaming agents for major gas fields in China

The conventional foaming agents have the problems of poor adaptability and high cost during the application in different types of gas fields,especially in high temperature,high salinity,high acidic gas and high condensate oil and gas fields.In this study,the Gemini foaming agent was used as the main agent to enhance foaming and foam stability of the foaming agent,the grafted nanoparticles were used as foam stabilizer to further improve the foam stability,and the characteristic auxiliaries were added to make the foaming agent suitable for different types of gas reservoirs.Two types and six subtypes of nanoparticle foaming agents have been prepared for the main gas fields of China.The experimental evaluation results show that the overall temperature resistance,salinity resistance,H2S resistance,CO2 resistance and condensate resistance of the nanoparticle foaming agents can reach 160℃,250000 mg/L,100 mg/L,100%and 40%,respectively.The new foaming agents have been used in 8685 wells in China.Compared with conventional foaming agent,the average gas flow rate per well increased by 62.48%,the pressure difference(casing-tubing)decreased by 18.9%,and the cost dropped by 45%.The effect of reducing cost and increasing efficiency is obvious.

Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion(Ⅱ)

During the fixed bed tube furnace combustion experimental study,stimulated the calcium-based sorbent grain size and microstructured influencing factors to explain the fluorine retention effect influence law,and expounded the combustion fluorine retention agent developing principle,and probed into the high-temperature fluorine retention agent technical approach.The results show that the calcium-based sorbent particle grain size and pore structure also have the bigger influence on the combustion fluorine retention ef- fect,and reducing the calcium-based sorbent particle grain size and improving the calcium sorbent structure characteristics at very high temperature to enhance the fluorine retention effect is the important approach to the fluorine retention agent development.

Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion(Ⅰ)

In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.

STUDY ON A NEW NONIONIC MICRIOPARTICLE RETENTION SYSTEM

The retention and drainage performances of microparticle retention system were studied in this paper, through measuring the improvement of beaten degree and retention ratio of slurry. The effects the retention system on paper sheet were discussed by measuring physical properties of paper. Compared with the influence of Hydrocol system (CPAM/bentonite) on the aspects of retention aid and drainage properties as well as increased product cost per ton paper, the developed nonionic system has some superiority and better practicability.

保水剂施用量对西南紫色土水分和养分特征及烟叶品质的影响

[目的]揭示保水剂聚丙烯酸钾不同施用量对西南烟区紫色土水分、土壤孔隙状况、土壤养分特征及烟叶品质的影响,为缓解季节性干旱区植烟土壤水分缺乏及高产优质的烟草生产提供重要参考。[方法]采用随机区组设计,定量研究了不同保水剂施用量条件下的紫色土水分、养分及烟叶品质特征。[结果]保水剂添加后,土壤pH值变化范围为7.4~7.7,土壤总孔隙度、毛管孔隙度、土壤饱和含水量、田间持水量、毛管含水量均呈先增大后减小变化规律,当保水剂施用量为150 kg/hm^(2)时,土壤容重达到最低值,土壤总孔隙度和毛管孔隙度、土壤饱和含水量、毛管含水量均达到最大值。土壤的阳离子交换量(CEC值)呈现出波动式变化。土壤有机碳、全钾和速效钾含量随着保水剂施用量的增加呈先增加后降低的趋势,土壤全氮、全磷、碱解氮和速效磷含量呈逐渐增加趋势。土壤容重呈现出先减小后增大的趋势。烟叶氯含量、总氮含量变化为上部叶<中部叶<下部叶。随着保水剂施用浓度的增加,烟叶氯含量呈波动变化。中上部烟叶含钾量高于下部烟叶含钾量且随保水剂施用浓度的增加略有增加。烟碱含量变化为上部叶>中部叶>下部叶,且烟碱含量与保水剂施用浓度相关性较弱。烟叶还原糖和总糖的变化趋势较为一致。不同部位的烟叶钾氯比表现为上部叶>中部叶>下部叶,且最随着保水剂施用浓度的增加,烟叶钾氯比呈波动态变化。不同叶位烟碱/总氮比和糖碱比均表现为上部叶<中部叶<下部叶,且随着保水剂浓度的增大,均表现为递增趋势。植烟土壤全氮含量与不同叶位的烟叶氯含量、上部叶含钾量、还原糖含量之间均呈显著正相关关系(p<0.05)。不同叶位烟叶氯含量、还原糖含量、上部烟叶钾含量、下部烟叶烟碱含量均与土壤有机碳间存在显著正相关关系(p<0.05)。[结论]保水剂为150 kg/hm^(2)对于西南紫色土的改良效果最佳,研究可为植烟土壤抗旱性能增强及烟叶品质的提升提供科学依据。

矿井高效抑尘剂优化配方及性能研究

以某煤矿掘进工作面粉尘为研究对象,开展矿井高效抑尘剂优化配方及性能研究。通过沉降实验,确定高效抑尘剂优化配方的润湿剂组分为2%的TX-100和0.5%的SDBS混合溶液;通过黏度测定实验,确定优化配方的黏结剂组分为E412;通过保水性实验,确定优化配方的保水抑尘剂组分为PAAS;通过抑尘剂溶液的酸碱度测定实验,确定选用PHOS调节溶液的pH值为6.8;最终研究得到矿井高效抑尘剂GHY-1配方组分及比例。性能测定实验结果表明:高效抑尘剂优化配方表面张力为68.15 mN/m,左、右接触角分别为11.25°和10.85°,黏度值为0.4mPa·s,保水率为80.5%,降尘效率可达95.3%。

膨润土在助留助滤体系中加入顺序的探讨

为达到CPAM/膨润土助留助滤体系最佳的使用效果,对CPAM/膨润土助留助滤体系中膨润土的加入顺序进行了实验室小试,在所有添加条件不变的情况下,先加CPAM再加膨润土时留着率和滤水效果明显好于先加膨润土再加CPAM,根据小试结果对大生产中膨润土的加入点进行了调整,取得了较好的效果。

气井排水采气用纳米泡排剂研究及性能评价

泡沫排水采气是含水天然气井开采中后期较为常用的一项技术措施。为了进一步提高页岩气井排水采气用泡排剂的泡沫稳定性能,通过大量室内实验,优选出性能较为优良的起泡剂BY-1和稳泡剂HW-3,并通过引入纳米颗粒来提高泡沫体系的稳定性能,研究出一种适合页岩气井排水采气用纳米泡排剂体系,评价了体系的耐温、耐盐和耐油性能。结果表明:纳米泡排剂体系的耐温性能较好,随着老化温度的增高,体系的起泡体积和泡沫半衰期均先增大后减小,当老化温度为120℃时,起泡体积和泡沫半衰期仍能达到450 mL和330 min;纳米泡排剂体系的耐盐性能较好,随着矿化度的增大,体系的起泡体积逐渐减小,泡沫携液率先减小后增大,当盐水矿化度达到1.0×10^(5)mg·L^(-1)时,体系的起泡体积和泡沫携液率仍能达到425 mL和80.6%;纳米泡排剂体系的耐油性能较好,随着煤油体积分数的增大,体系的起泡体积和泡沫携液率均逐渐减小,当煤油体积分数为30%时,体系的起泡体积和泡沫携液率仍能达到420 mL和50.7%。

耐油泡排剂Facam的制备和性能研究

为提高凝析气井的泡沫排液效果,研制阴离子、阳离子与两性表面活性剂三元复配耐油泡排剂(Facam),采用泡沫仪、界面张力仪、黏度仪等测试其泡沫性能、耐油性能和泡沫乳液黏度,并应用于凝析气井排液采气作业。结果显示,与两性表面活性剂(LB1)相比,油滴在Facam液膜上的铺展系数小于0,表明在高含凝析油条件下Facam的泡沫稳定性得到提高,同时,Facam产生的乳液黏度较低,可降低由摩擦阻力损失引起的油管压降。现场气井注入Facam后,油套压差(ΔP_(c-t))从1.00 MPa降低到0.28 MPa,产气月度递减率降低到2.86%,排液采气效果优于LB_(1),有效保证气井稳产。

NaHCO_(3)和KHCO_(3)复合保水剂对凡纳滨对虾虾肉保水效果的影响

【目的】探究复合添加NaHCO_(3)、KHCO_(3)两种无磷保水剂的添加量和浸泡时间对凡纳滨对虾(Litopenaeus vannamei)虾肉保水能力的影响。【方法】通过不同添加质量分数(0.5%、1.0%、1.5%、2.0%、2.5%、3.0%)的NaHCO_(3)和KHCO_(3)两种保水剂及浸泡时间单因素实验,分析NaHCO_(3)和KHCO_(3)对凡纳滨对虾虾肉pH、浸泡增重率、蒸煮损失率等指标的变化;并对NaHCO_(3)和KHCO_(3)联合使用时的添加质量分数和作用时间进行响应面优化,确定最佳添加量及浸泡时间;以电位、水分分布、微观结构等指标分析不同保水剂对虾肉蛋白的内在影响。【结果】单因素实验结果表明,添加NaHCO_(3)和KHCO_(3)能有效提升虾肉保水效果,且均在添加质量分数为2.0%时保水效果最佳。浸泡6~15 h间,虾肉pH和浸泡增重率变化较小。响应面优化结果表明,NaHCO_(3)和KHCO_(3)添加量存在交互影响,复合添加1.5%NaHCO_(3)和1.5%KHCO_(3),浸泡9 h后虾肉有较高的浸泡增重率(22.65%)和适宜的pH(8.06)。保水剂对蛋白的影响表明,复合保水剂添加主要通过促进虾肉蛋白的电位增加、自由水增加、分子解离及凝胶结构的形成来提高虾肉的保水能力,其保水能力强于添加质量分数0.5%复合磷酸盐组。【结论】联合添加使用质量分数1.5%NaHCO_(3)与质量分数1.5%KHCO_(3)并浸泡9 h处理,可增加虾肉肌原纤维蛋白分子电位、增强虾肉蛋白凝胶网络结构、改变虾肉内部水分分布,对提升虾肉保水能力有明显作用。

一种煤粉悬浮剂的实验研究及注入工艺

煤层气排采过程中,地层产液携带煤粉进入生产管柱中,随着中后期产液量下降,若煤粉不能及时从泵筒和油管中被携带至地面,而在泵筒中沉淀,使凡尔不能复位造成泵漏失,甚至煤粉堆积造成卡泵、埋泵等井下故障,会严重影响煤层气开采效率。针对煤粉沉积的问题,采用往井筒中注入一定配比活性剂的悬浮液,悬浮液具有在低浓度时吸附在煤粉表面使其悬浮于水中的特性,降低临界携煤粉流速。在此基础上,通过有杆泵使井筒中悬浮的煤粉尽快返排至地面,以减少对井筒的伤害。通过实验方法测试出粒径100目(0.150 mm)以下的煤粉在不同质量分数表面活性剂作用下,最大悬浮率可达28.57%,在排液采气流量不变的情况下,有效提升了煤粉携带的性能,降低因煤粉堵塞原因引起的油气田主流生产泵的故障率,煤层气的长效排采对气田稳产、高产具有重要意义。

水基型灭火剂扑救液体火灾关键性能对比研究

为了进一步规范泡沫灭火剂和水系灭火剂等水基型灭火剂的适用火灾类型和灭火应用场景,厘清对上述两类灭火剂的认识误区,选择应用广泛的水成膜泡沫灭火剂和水系灭火剂,按照GB 15308-2006《泡沫灭火剂》规定的标准试验方法对表面张力、界面张力、发泡倍数、25%析液时间以及灭火性能进行对比试验研究。研究结果表明,水基型灭火剂使用泡沫产生装置应用时,水成膜泡沫灭火剂的关键性能特别是灭液体火效果优于水系灭火剂,绝大多数水系灭火剂达不到对于液体火灾的理想扑救效果。因此,基于对比试验结果和产品标准对水基型灭火剂的性能要求,建议水系灭火剂应用场景为充装水基型灭火器、扑救固体和液体初起火灾,泡沫灭火剂则应结合固定式泡沫灭火系统和消防车等移动式灭火装备,扑救石油化工储罐等场景下的大型液体火灾。

EPEG型聚羧酸保坍剂的制备及性能研究

以乙二醇单乙烯基聚乙二醇醚(EPEG)、丙烯酸羟丙酯(HPA)、丙烯酸(AA)为主要原料,在常温条件下通过自由基聚合合成聚羧酸保坍剂。通过试验考察了釜底浓度、反应温度、引发剂、链转移剂用量及酸醚比对产品性能的影响。最佳反应条件:HPA∶AA∶EPEG=3.5∶1.5∶1.0,引发剂占单体质量百分比为1.2%,滴加时间为60 min,保温30 min,反应结束。通过对EPEG和TPEG大单体核磁对比分析,以及EPGE与TPEG型保坍剂进行凝胶渗透色谱(GPC)、总有机碳分析仪(TOC)微观分析,证实了EPEG型保坍剂具有更优性能的微观原因。在达到相同保坍性能条件下,EPEG型保坍剂只占TPEG型保坍剂用量的80%,大幅降低了保坍剂用量,显著节约成本,大幅提高市场竞争力,同时EPEG型保坍剂常温、短时间、高效率的生产特点,使其具有良好的经济价值及广泛的应用前景。